Kerry's Syria Campaign Likely to Define His Legacy

WASHINGTON—U.S. Secretary of State John Kerry has been on the international stage for nearly four decades. But his campaign against Syrian President Bashar al-Assad likely will define his diplomatic legacy.

In a little over two years, the former senator from Massachusetts, who took the helm at the State Department in February, has morphed from Washington's leading advocate for engaging Syria's 47-year-old dictator to taking much more...